Freezing unit for household refrigerators



0d. 24, 1933. KNAPP FREEZING UNIT FOR HOUSEHOLD REFRIGERATORS Filed Oct. 31, 1929 ding-5.

l7 Lueflbb'fw V Leland 6% Knapp. 56 M WW Fatentedl @ct. 2 11.93335 hurrah stares lhl hlhil *hlilh IFEElEIEZllNG UNIT IFKBR IHIQUSIE HQLD REFIEKGERA'JIQNRZS Leland G. Knapp, (Chicago, 111111., assignor to Montgomery Ward & Co llncorporated, (Chihcago, 111111., a corporation of lllllinois Application (Dctoher 311, 1929. Serial No. dilhiiilh 8 @Jlzrlmus.

Heretofore it has been the general practice in constructing freezing units' to provide a casing in which is mounted the expansion coils of the cooling system. The unit is then filled with alcohol, glycerine or a saline solution to aid the conduction of heat from the walls of the casing to the expansion coils. This type of unit is in- 'eficient in that the heat conductivity of the have not proved particularly satisfactory.

The object of the present invention is to pro= vide a freezing unit which is highly efficient and which may be manufactured at a relatively low cost.

A further object of the invention is the provision in freezing units of a non-fluid heat-conduct ng medium of high eficiency.

Qther objects and advantages of the invention will be obvious to those skilled in the art upon understanding the principles thereof.

For pinposes of illustration there is shown, in the accompanying drawing and herein described, a preferred embod ment of the inven= tion. It is to be understood that this disclosure is given for purposes of exemplification only as it will be obvious to those skilled in the art that many changes may be made in the device and the method of making the same without departing from the true scope and spirit of the in vention as defined by the appended claims.

Referring to the drawing:

Fig. l is a top plan view showing in dotted lines the expansion coils mounted in the unit;

Fig. 2 is a sectional view on the line 2--2 of Fig. l the top, however, being shown as spaced from the body of the casing; and

Fig. 3 is a sectional view on the line 3-'-3 of Fig. l.

The unit comprises a casing or housing indicated in the drawing by the numeral 11 which is substantially rectangular in outline and is providedat its upper edge with a closure cap 12. Within the casing 11 and open ng at the ends thereof is arranged a spaced chber 13 which is subdivided into a plurality of freezing compar iaments 14. These compartments may be used a receive the usual ice trays for the freezing of ice cubes or for other purposes when a frozen' product is desired. By reason of the spacing of ((011. ca -es) the chamber 13 with respect to the outer walls or the casing, spaces 15 are provided which communicate with an upper space 16 located above the chamber 13 between'the top thereof and the closure cap 12. Z'he spaces 15 and it re- .ceive the expansion coils 17 of the refrigerating system. i'hese coils are of suitable length and material and are shaped to conform with the requirements of the-unit.

The ends of the coils l? have secured thereto coupling sleeves 18 which pass through openings 19 provided in the cap 12. The inner ends or the coupling sleeves are provided with flanges at that seat on the inner face of the cap 12 and the outer ends are screw-threaded to re-. ceive clamping nuts 21 which firmly secure the sleeves to the cap. 1

If it is desirable to utilize the greatest possible cooling effect of the unit in. the box, fins 22 may be provided which project from the outer surfaces of the unit.

Heat-conducting material 23 consisting of a finely divided substance having relatively high heat conductivity is interposed between the coils l7 and the walls of the casing in order that the heat absorbed try-the walls of the casing may be quickly and efiectively removed from the in the expansion coils 17. I

A binding medium may be used for retaining the subdivided heat-conducting material in place although such medium is not necessary. It has been found, however, that by using a binding agent which fills the interstices in the subdivided material a more efficient unit results; due to the fact that the air which would act as an insular-- tor, is removed therefrom. A binding agent also irmi, cements the coils in place and prohibits any movement thereof due to handling, vibration or other causes which might weaken them or cause their rupture.

It is desirable that the subdivided heat-conunit by the action of the refrigerating medium ducting material be very finely divided in such to as filings or shavings, although the device efiective and fairly emcient ii the heat-condill.

which is capable of freezing water in the freez-' ing compartments in approximately one-half the time required in the units now. generally on the market.

Aqueous solutions of sodium silicates which do not chemically react with aluminum or the metal used are particularly adapted for use as a binding agent as they may be had in liquid form at normal temperatures and readily permeates the finely divided heat-conducting substance. A further advantage of sodium silicates of the class referred to is that by applying heat thereto the .moisture may be driven 01f quickly and the binder reduced to a dry, hard state. The hardness of the silicates when dry forms a solid block which, forall practical purposes, is indestructible. Obviously, many binding agents may be substituted for sodium silicates such as potassium silicates, shellacs, varnishes and other well known materials.

The method of manufacture of the device is simple, does not require special equipment and the materials are relatively inexpensive. In assembling the device, the coils 1'7 are placed in the casing 11 with the cap 12 removed therefrom. The subdivided heat-conducting material is poured into the casing completely covering and surrounding the coils except, possibly, portions thereof which may be in direct. contact with the casing. The binding agent is then poured over the heat-conducting material, permitted to percolate therethrough and is hardened. The hardening of the binding agent in the case of sodium silicates and like substances is accomplished by placing the unit in an oven and raising the temperature sumciently to drive off excess moisture. The cap 12 is then mounted on the device and secured in place.

If desirable, the cap may be placed on before the hardening step provided a space is left be-' tween the edges of the cap and the casing to permit the escape of water vapors or a hole may be provided in the. cap in which event the cap is secured in place and an opening left therein which is subsequently filled by an ordinary screwthreaded plug.

In cases where it is desirable to freeze a large amount of material, such as ice cubes, but in which the heat to be conducted from the ice box or similar equipment is less than would normally be absorbed by a unit of sufficient size to freeze the desired amount of material, the fins 22 may be omitted from the structure, and, if necessary, one of the outer walls of the casing may be insulated from the coils 16 by interposing a sheet of insulated material 24 between the outer wall of the casing and coils. A convenient and effective way of providing this insulation is by pouring a layer of paraffin, wax or other similar substance on the top of the finely divided heatconducting material so that the cap 12 is insulated from the rest of the unit.

The freezing unit herein described has been found to be highly efficient and is adapted for manufacture from relatively inexpensive materials which are quickly and easily assembled.

I claim: 7

1. A refrigerating unit comprising a casing, conduits for circulating a refrigerant within said casing, and finely subdivided aluminum interposed between said conduits and said casing, said aluminum being held in place by a binding medium.

2. A refrigerating unit comprising a casing,

conduits for circulating a refrigerant within said casing, finely subdivided aluminum. interposed between said conduits and said casing, and a v binding agent consisting of sodium silicate.

3. A refrigerating unit comprising a casing, means" for introducing a refrigerant into said casing, subdivided heat-conducting substance interposed between said last mentioned means and a portion of said casing, and a heat insulating material interposed between a portion of said heat-conducting substance and said casing.

4. A refrigerating unit comprising a casing, means for introducing a refrigerant in said casing, means for conducting the heat from a portion of the walls of said casing to said refrigerant, and a layer of heat insulating material positioned between one wall of said casing and said heat-conducting means. 1

5. The method of making refrigerating units which comprises placing refrigerating coils in a casing, filling the casing with subdivided material, pouring a binding agent over the subdivided material and applying heat to solidify the binding agent.

6. The method of making refrigerating units which comprises placing the refrigerating coils within the container therefor, filling the container and covering the coils with a subdivided heat-conducting material, pouring a binding agent in liquid form over the subdivided material permitting the same to percolate therethrough and applying. heat to the unit to solidify the binding agent.

'1. A refrigerator cooling unit comprising spaced inner and outer shells, a coil arranged therebetween, and a filling occupying the remaining space between said shells, said filling comprising metallic particles and self-hardening binding material therefor.

8. A refrigerator cooling unit comprising spaced inner and outer shells, a coil arranged therebetween, and a filling occupying the remaining space between said shells, said filling comprising metallic particles and self-hardening binding material therefor having a relatively high coeficient of heat conductivity.

LELAND G. KNAPP. 

